1. Field of the Invention
The present invention is related to a method for adjusting a backlight of a display device, and more particularly, to a method for adjusting a backlight of a display device according to image loading and edge statistics of an input image.
2. Description of the Prior Art
A conventional display device utilizes dynamic backlight control as a measure for lowering power consumption. Dynamic backlight control adjusts backlight luminance according to image loading of a display image. For instance, the image loading of a display image usually means an average grayscale of the display image.
Please refer to FIG. 1. FIG. 1 is a diagram illustrating the conventional display device adjusting backlight luminance utilizing dynamic backlight control when the display image is a dark scene. Since the display image is a dark scene, the display image comprises relatively low image loading. Therefore, when displaying the display image, the display device reduces the backlight luminance from a default 100% (curve C) to 30% (curve C′), as shown in FIG. 1, for lowering power consumption. Assuming the display image includes an object, and the object is between a grayscale of 100 and 150, a corresponding dynamic range Dr is approximately between a luminance of 70 and 200. After the backlight is adjusted through dynamic backlight control, the dynamic range Dr is approximately compressed to a dynamic range Dr′ with a luminance of 23 to 66. A low dynamic range means less precision in intensities represented by each pixel, i.e. details of the object may not be fully presented. Therefore, for the conventional display device utilizing only image loading to adjust backlight luminance, when the display image is a dark scene and includes an object, the adjusted backlight luminance may be too low, so details of the object cannot be fully presented, consequently affecting quality of the display image.